Wireless charging systems and wireless charging devices are well known in the art. Some examples of such charging systems and devices that are using electromagnetic energy for charging are described in details in international patent publications Nos. WO 2013/118116, WO 2013/179284, and WO 2015/022690 of the same inventor all incorporated herein by reference.
The basic condition for successful and efficient charging in all wireless charging systems based on electromagnetic radiation transmission is to achieve high coupling and high transfer efficiency between the transmitting probe and the receiving probe, i.e. between the transmitting unit of the wireless charging device and the receiving unit of the device under charge (denoted herein after: “DUC”).
High coupling between the transmitting probe and a receiving probe is usually obtained in stable unchanging systems where the position and location of the probes are fixed. However, in wireless charging systems, there is a need to allow a certain amount of flexibility and freedom of movement between the transmitting component and the receiving component, so as to maintain high transfer efficiency between the probes regardless of the position and orientation of the chargeable device, since a user may position the device under charge onto/within the wireless charging device in each charging session in a different position and/or orientation.
When using a single probe the ground plat of the receiving unit is used as a RF ground to the receiving probe. However, this ground is significantly small and thus, any environmental changes are influencing the electromagnetic field lines distribution between the probe and the ground, i.e. the sensitivity of the receiving probe as to changes in its position and/or orientation is high.
The sensitivity of a single probe to elements around it is further enhanced when charging is conducted in a close/partially close conductive structure. In such scenario, the charging system is usually designed to obtain high coupling and to have high efficiency of energy transfer at certain position of the transmitting probe relative to the receiving probe as the receiving probe is referenced to specific ground point in the charging system. Upon changing the position and/orientation of the DUC within the charging zone, the steady state of the wireless charging system as designed is breached as the interaction of the receiving probe with the elements around it, such as but not limited to, the walls of the conductive charging device and the transmitting probe changes. This change breach the conditions required to obtain high coupling between the transmitting and the receiving units as the electromagnetic field lines distribution between the receiving probe and the RF ground are being change and interact with other elements in the surrounding, and consequently, the transfer efficiency between the units significantly decreases.
The present invention is aimed to provide a novel probes arrangement configured and operable to improve the stability and the flexibility of the coupling between the charging device and the device under charge by enhancing the stability of the RF coupling between the transmitting and the receiving units and maintaining high transfer efficiency between the units, in a dynamic charging system where the position and the orientation of the device under charge changes from one charging session to the other. The novel probes arrangement may be used in different environments including wireless charging systems within a close/half close charging chamber and open near field environments.